Question

Three consecutive resonant frequencies of string are $90,150$ and $210Hz.$ If the length of the string is $80cm$ what is the speed of the transverse wave in the string ?

• A. $45m/s$
• B. $96m/s$
• C. $48m/s$
• D. $80m/s$

Answer 1

Answer: (B)

$96m/s$

The given frequencies are third, fifth and seventh harmonic. So, the fundamental frequency is $30Hz$.
$\frac{\lambda }{4}=0.8\Rightarrow \lambda =3.2$
Hence wave velocity $v=\nu \lambda =30\times 3.2=96m/s$